Recent clinical trials of peptide vaccine for cancer patients have rarely resulted in tumor regression. One of the reasons for this failure could be an insufficient induction of anti-tumor responses in these regimens, in which peptide-specific memory cytotoxic T lymphocytes (CTLs) were not measured prior to vaccination. We investigated in this study whether pre-vaccination measurement of peptide-specific CTLs can provide any advantages in lung cancer patients receiving peptide vaccination with regard to safety and immunological responses. Ten patients with advanced lung cancer received vaccination with peptides under a regimen of CTL precursor-oriented vaccination, in which pre-vaccination peripheral blood mononuclear cells (PBMCs) were at first screened for reactivity in vitro to each of 14 peptides, followed by in vivo administration of only the reactive peptides. Profiles of the vaccinated peptides varied markedly among the 10 patients. This regimen was generally well-tolerated, although local skin reactions, diarrhea, and colitis were observed in 8, 2, and 1 patient, respectively. Increased CTL responses against the immunized peptides and tumor cells were observed in the post-vaccination PBMCs from 4 of 8 and 3 of 10 patients tested, respectively. Peptidespecific IgG became detectable in post-vaccination sera in 4 of 10 patients tested, and these 4 patients had a long progression-free survival. Furthermore, the median survival time of 9 patients with non-small cell lung cancer was 668.0 ± ± ± ±164.2 days. These results encourage further development of CTL precursor-oriented peptide vaccination for lung cancer patients. (Cancer Sci 2003; 94: 548-556) dentification of a large number of antigenic epitopes 1-9) recognized by cytotoxic T lymphocytes (CTLs) reacting to tumor cells has opened the door to clinical trials of peptide-based immunotherapy for cancer patients. [10][11][12][13][14][15][16] Many clinical trials of peptide-based immunotherapy for malignant melanoma and other epithelial tumors have been conducted in the past decade, but major clinical responses were rarely obtained in these clinical studies, including our trial of a cyclophilin B (CypB) peptide vaccination for advanced lung cancer patients 17) and a SART3 peptide vaccination for advanced colorectal cancer patients.18) One reason for this failure to obtain tumor regression could be an insufficient induction of anti-tumor responses in these vaccine regimens, in which peptide-specific memory T cells were not measured in pre-vaccination peripheral blood mononuclear cells (PBMCs). We have speculated that vaccination based on information from pre-vaccination measurement of peptide-specific CTLs in the circulation might induce potent anti-tumor immune responses in cancer patients. This hypothesis is based on the assumption that initiation of immune-boosting of CTLs through peptide vaccination could be more effective than immune-priming of naive T cells with regard to induction of prompt and strong immunity to both the peptide and tumor cells. We ha...

Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge1–5. Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target.

Cyclophilin B (CypB) possesses two antigenic epitopes (CypB(84-92) and CypB(91-99) ) recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs). To determine the safety of CypB-derived peptides and its ability to generate antitumor immune responses, patients with advanced lung cancer received subcutaneous vaccinations of these peptides or their modified peptides. All 16 patients were vaccinated with CypB(91-99) or its modified peptide, whereas only two patients were vaccinated with the modified CypB(84-92), as immediate-type hypersensitivity to CypB(84-92) or its modified peptide was observed in the remaining patients. No severe adverse events were associated with the vaccination. No significant increase in cellular responses to either peptides or tumor cells was observed in the postvaccination PBMCs by the conventional CTL assays in any patients tested. These results suggest that the vaccination of CypB(91-99) peptide was safe, but failed to induce objective immune responses at this regimen.

The PCR-invader method was useful for detecting EGFR mutations in clinical lung cancer specimens and is more sensitive than direct sequencing.

In most protocols of peptide-based vaccination, no consideration has been paid to whether or not peptide-specific cytotoxic Tlymphocyte (CTL) precursors are pre-existent in cancer patients. Initiation of immune boosting through vaccination is better than that of immune priming to induce prompt and strong immunity. In this study, 10 human histocompatibility leukocyte antigen-A24 þ patients with advanced colorectal carcinomas were treated with up to four peptides that had been positive for pre-vaccination measurement of peptide-specific CTL precursors in the circulation (CTL precursor-oriented peptide vaccine). No severe adverse effect was observed, although local pain and fever of grade I or II were observed. Post-vaccination peripheral blood mononuclear cells (PBMCs) from five patients demonstrated an increased peptide-specific immune response to the peptides. Increased CTL response to cancer cells was detected in post-vaccination PBMCs of five patients. Antipeptide immunoglobulin G became detectable in postvaccination sera of seven patients. Three patients developed a positive delayed-type hypersensitivity response to at least one of the peptides administrated. One patient was found to have a partial response; another had a stable disease, sustained through 6 months. These results encourage further development of CTL precursor-oriented vaccine for colorectal cancer patients.